Composition of matter and method of making the same



106. COMPOSITIONS,

COATING 79 R PLASTIC.

Patented Dec. 26, 1933 coMPosrTmN or Hamid 11. Jordan, Manheim Township, Lan

caster County, Pa., assignor to Armstrong Cork mpany, Lancaster a Pennsylvania I No Drawing.

, Pa, a corporation of Application November '17, 19:1 4 Serial No. 575.639

4 Claims. (01. nae-es)" My invention relates to a composition of matter all or a portion of the reclaimed rubber. Whenand to the method of making the same. It provides a material which may be in sheet form or may be molded or worked into any desired shapes. My material may be used to form stoppers, gaskets, washers and the like.

It is an object of my invention to provide a material that will be extremely resistant to attack by organic solvents. It is a further object of my 1 invention to provide a composition of matter go My new composition consists of cork filler, a

casein binder and a glue binder. Although the proportions of the materials may be varied, I

ever crepe rubber is used, the casein, glycerine, sodium silicate, triethanolamine, and reclaimed rubber, if any, is used, is put on the mixing rolls and the mass is mixed until it becomes soft. Then the crepe rubber is added and the mixing is continued until the mixture is homogeneous. Latex may be used in place of the reclaimed rubber without any special mixing operation.

Instead of using triethanolamine I may substitute either monor diethanolamine. It is also possible to use other organic amfies such as the methanolamines or ro anolamines. It will heme exact percenta-g'e of organic alkali used will depend upon the alkalinity Exaniihoi UNITED STATES PATENT. em e f or MATTER AND METHOD MAKING THE same of the particular alkali or combination of alkalies used. A

The glue binder I prefer to use contains approximately 43% lue 43% l cerine and 14% water The water causes the g ue 1n er to swell. Me binder is tougher andmore flexible than the casein binder and imparts these characterprefer to use approximately 59.2% of g. istics to the casein binder when the two are combinder 16% of a glue binder and 24.8

er. A preferred form of casein binder consists of L Percent Case n 32.7 Glycerine P 37.15 Reclaimed rubber 12.75 Sodium silicate 12.4 Triethanolamine 5.0

binder on mixing rolls until the casein has been properly dispersed. The mixing rolls are maintained at a temperature of from 180 to 190 F.

The glyoerine is used as a plasticizer and pre- The casein is dispersed suiilciently when specks vents the composition from becoming horny in of casein are no longer visible in the composition.

character. The reclaimed rubber is used in col- The glue binder is then added and the mixing loidal dis rsion a s rong a uch as W continued until a homogeneous mass is obtained. fidfoxiae, potassium hydroxide or sodium car- After the glue and casein binders have been '5 nate. Tie s -i slicate E that m own com-" mixed until a homogeneous mass is obtained 1 merc1'afiyas"Ngrade and contains approximately the cork flller is added while the material is still 62.1% of water. The triethanolamine is an organic alkali and is used to produce a more alkaline reaction with less liquid. The sodium silicate also tends to increase the alkalinity of the binder. The triethanolamine and the sodium silicate together cause the swelling of the casein. The swelling of the casein changes it from a solid to a gelatinous material. Apparently when the casein swells it forms a protective coating around 3.50 the rubber molecules. The rubber increases the toughness and tensile strength of the composition but is not aflected by the organic solvents. The -plete. The composition may be reworked on triethanolamine also adds to the toughness and warm rolls any time prior to the completion of flexibility of the composition. the tanning reaction. In orther words, my comobtained is allowed to cure for one day. The curing period increases the tensile strength of the composition and toughens it.

45 For most purposes the tannin naturally prescasein binder. As soon as the casein and glue are reacted by tannin a chemical reaction takes place causing the glue and casein to become insoluble. About nine months to one year is rerss latex or crepe rubber may be substituted for position may be kept up to about nine months 110 on the mixing rolls. The homogeneous mass thus ent in the cork is suflicient to tan the glue and without affecting its workability. This time is sufliciently long so that after I make my composition and stamp out stoppers, gaskets, washers,

or the-like, I'may rework the scrap without any trouble -and stamp out additional articles. "In this manner all waste material is substantially eliminated. Other cork compositions become practically unworkable it they are allowed to stand for any length of time after they are formed. My composition retains its workability because the protein is not completely tanned and the rubber is not vulcanized.

My composition is particularly suitable for-use in making gaskets for sealing organic compounds such as esters, ketones and alcohols. Although the protein is not completely tanned and the rubber is not vulcanized, my composition has an extremely high tensile strength and is very flexible.

In many instances it is possible to use mycom- 9,0 position as asubstitute for leather.

Additional tanning agents such as formaldehde or ammonium dichromate may be added to e coming is desired. Immediate tanning might be desirable where it 35 is desired to use the material for making oil pump gaskets. case the tanning would be desirabiegto prevent the "softening of the glue and casein by the frictional heat developed by the piston. In some casesit may also be desirable to add an accelerator to vulcanize the rubber in the composition to obtain a tougher product. Neither the tanning action nor the vulcanization of the rubber has any effect on the composition as :far jasxits resistance to organic solvents is concemed. However, either-of these reactions will prevent reworking of the composition.

while Ihave described a preferred embodiment 'fif'myipvention and indicated certain uses for the material it will be understood, however, that 40 lsby way of illustration only and that vari- 2.. .1 0 1. A plastic composition of matter free of ma- "terials soluble in organic solvents capable of being worked and cured and reworked after curing into a gasket for organic solvents comprising a casein compound, plasticized glue and comminuted cork, said casein compound including rubber, glycerin and an ethanolamine, said rubber being isolated by a protective colloid formed of ethanolamine caseinate. 2. A plastic composition of matter made in ac cordance with the method of claim 3 and com- -prising a casein compound, plasticized glue, comminuted cork and a tanning agent, said casein compound including rubber, glycerin and an ethanolamine. "3. -In the method of making a' composition of matter for 'use in-the manufacture of gaskets and the like, the steps consisting in milling at'an elevated temperature a compound including casein, glycerin, rubber and an ethanolamine; introduci ing a plasticized glue while continuing the mill-; ing; adding comminuted cork; milling the mass -'until a homogeneous mix is obtained and curing themix.

4. In the method 'of making a 'composition ot matter for-use in the manufacture of gaskets and the like, the steps consisting in milling at an elevated temperature a compound including casein, glycerin, rubber and an ethanolamine; introducing a plasticized glue while continuing the mill- I10 ing; adding comminuted cork and a tanning agent; milling the mass until a homogeneous mix is obtained and curing the 3 

